Spinning cuprammonium silk by the stretch process



Oct 20, 1931.

A. H ARTMANN ETAL SPINNING CUPRAMMONIUM SILK BY THE STRETCH PROCESS Filed Sept. 3, 1950 1 l l J z 3 Sheets-Sheet 1 INVENTORS fiugas? liar'imaazrz,

W4 Zier ##igijf BY-MW ATTOR N EV 2 1931- A. \HARTMANN ET AL ,8

SPINNING CUPRAMMONIUM SILK BY THE STRETCH PROCESS Filed Sept. 3, 1950 3 Sheets-Sheet 2 I N V ENTO RS flzgusi Hariinann WaZier H6 in 710 7 M fl w/V ATTORNEY Oct, 20, 1931. AJHARTMANN ETAL SPINNING CUPRAIIMONIUM SILK BY THE STRETCH PROCESS 5 Sheets-Sheet s Filed Sept. 3, 1930 INVENTORS flu ds? fiarimann/ h/a ATTORNEY- Zia BY Patented Oct. 20, 1931 I UNITED ST PATEN }OFFICE I 7 ing the exit of the thread from apparatus at varying rapidity;

. I WUPPERTAI B-ARMEN, GERMANY,

ASSIGNGRS TO;AMERIC1AN TIOILYOZF NEW YORK, N; Y1, A'CORPOBATION G F DELAWARE- SPINNING CTTI'RAMMONIUM SILK BY THE STRETCH PROCESS' Application filed September 3, 193O, Serial" No..479,51'2, and in Germany August 29, 1929'.

In the processes heretofore known for spinningcupram-moniunr silk by the stretch-spinning process, the liquid jet coming out of the spinning apparatus surrounded the thread over a certain length of the same: In order to be able to subject the thread to anacid treatment the thread had to be separated from th e liquid. Hitherto this was effected by leading the thread around: a rod. This glves rise to a series of disadvantages. In the first place it was not possible to lead the thread into a hardening liquid directly after leaving the spinning apparatus; on the contrary, a further member must be inserted in tweemsinc'e' otherwise the hardening liquid mixes with the" precipitating liquid carried along with the thread'and its action is impaired. e v

furtherdisadvantage consists in the fact that the jet readily causes fracture of each individual filament if the thread is deviated from its-vertical direction, and: consequently from the freely falling stream of liquid, by means of the above mentioned rocL- Since the quantity" flowing through is not inconsiderable and, moreover, the exit-openingis somewhat narrow, so that in the case of diminished pressure in the spinning apparatusno air bubbles can penetrate into the spinning apparatus, the jet or stream of liquid liasacompara-tively high velocity, which still further facilitates the abovementioned fracturing of the individual filaments. Owing to theifacti that the in cons quence of the readily changing quantity and. velocity of the liquidflowing out, a braking eliect of varying strengthis produced and consequently a disadvantageous withdrawal ofthe thread from the spinning 'Thes e disadvantages are surmounted according: to the present invention by drawing the thread dbwnwards from thespinning zipparatus in a vertical direction without any liquid jet surroundingthesame; This is effeoted by drawing-oil? the liquid or deviating it fromthe path of'the'thread beforeo'r durapparatus; but before the collecting or guidingmember arr-anged behind the spinning tube is closed, the

friction on the rod varies;

, thesiphon tube, the

with: the thread. I

the spinning apparatus. In thism'anner' the thread directly arrives on or in the-further devices of the spinning apparatus only with the liquid adherent co-its surface.

For carrying out the process according to the'invention various devices may be used. Thespinning apparatus constructed in the usual manner" isprovided at one side, preferably just above the orifice, like tube: This siphon tube extends with its orifice'ov'er the orificeof'the exit pipe of the spinning apparatus and i's provided' with a tap; By suitable dimensionsof the siphon tube and oi the exit pipe the liquid may be madet e fl'ow' away through the siphon tube and the thread issue's freely from th'eeXit' pipe;- -If the tap in the siphon apparatus operates like .B MBERG CORPQ-RA whole of the a every known spinningapparatus, the-liquid V stream issuin vertically downwards with the thread. I n'eanetully' opening the tap the siphon t'u'be fills up and" a; stream of the spent precipitating liquid flows away theretl'irou'ghz If theorifice of the exit pipe is narrow" enough practically all thespent precipitating'liquid can be led-away through the siphon in any direction: and themoist thread alone leaves theorifice" in a vertical direc tion. The orifice-piped the spinning apparatus Inayal's'o' bev surrounded by a further collecting tube ori'fi'ce pipe by means of a plug. The siphon tube is then bran hed ofi'fr'omthe s'urroun'd" ing'tubel Thishad the advantage of being more readily exoh'angeablel p Since in the'course" of the s'pinningprooes s coppen" and cellulose precipitates deposit in ing through the latter tube continuously'be comes" smaller and} consequently more and spinning apparatus more liquid leaves the In" order to avoid this the" liquid flowing through the siphon tube: can be regulated by means 015 a tap; A finer-regulation maybe obtained by means of a vessel, adjustable as regards height, into whieh the siphon tube dips. By raising and lowering this vessel "the suction height maylikewise beadjusted quantity of liquid fio'y as desired. The device has the advantage that all valves and consequently all restrictions in the siphon tube are avoided, so that the danger of the formation of deposits in the siphon tube is diminished. Consequently, the quantity of the precipitating liquid flowing away through the siphon tube practically always remains the same; as a result it is ensured that the threadalways leaves the spin ning apparatus free from precipitating liquid or with an accurately adjusted small quantity of the same. In order to exclude the undesirable influence of depositsin the siphon tube the cross section of this tube is chosen as large as possible. A further advantage of the invention consists in the fact that a very finestepwise regulation. of the quantity flowing out of the outlet is possible by adjustment of the overflow vessel.

The process may also be carried out in practice by means of a special construction of the orifice of an ordinary spinning apparatus. It has been found that the jet of liquid coming out of the spinning apparatus may be deviated from the vertical direction taken up by the thread into an inclined direction. The orifice of the exit pipe is provided on one side with a small rod or a sheet metal strip attached at an inclination to the vertical. The adhesion of the precipitating liquid to the attached rod or metal strip is, in general, greater than the adhesion to the thread so that the desired separation is obtained.

Further only apart of the precipitating liquid can be led 0a through the siphon tube or the two said devices may be combined, both the siphon tube as well as the deviating metal sheet being arranged on the spinning apparatus. In the latter case it is possibleto lead off only a portion of the precipitating liquor before the exit orifice, and to deviate the rest while issuing from the exit pipe.

The process offers a series of advantages in spinning and permits of asimplified construction of spinning devices. Thus, the hardening liquid may be allowed to act on the thread directly after the issuance of the latter from the spinning apparatus without there being any danger of the precipitating liquor mixing with the'hardening liquid. It is only necessary to arrange 'one or several rods in an acid bath directly underneath the exit orifice of the spinning apparatus and to guide the thread, which is only superficially covered with precipitating liquid, directly round these rods. If one or more rollers are arranged behind this preliminary acidifying dev-ice, over which the thread is guided and treated by spraying with a further hardening liquid, then in this manner a stepwise acidification, first weak and then stronger, effect-ed.

A further advantage consists in' the fact that a driven roller may be arranged directly below the orifice of the spinning apparatus may be on to which the issuing threads may be directly guided and acidified by another hardening liquid, so that the winding rods hitherto usual, which frequently led to fracturing of the individual threads, are dispensed with. From this roller, upon which an acidification of the thread may be effected, the thread is led directly, or over a second roller, to a centrifuge, to a reel, or to a bobbin.

This arrangement has the advantage that it is possible to withdrawthe thread from the apparatus with perfectly definite and constant velocity, since no slipping takes place, but on the contrary the thread adheres to the roller and is carried forward'only by rotation of same.

Moreover, by using one of the two devices stretch-spinning in the vertical direction is rendered possible. For this the spinning apparatus, the guiding'and withdrawal rollers, and the receiving apparatus for the thread are arranged underneath one another in a vertical direction. In this way satisfactory supervision is" attained, as well as narrow machine construction and consequently considerable saving of space. In this arrangement the rollers are embraced by'the thread through an angle of 360. On account of this comparatively large angle this arrangement is particularly adapted for the stretchspinning process since slipping of the thread on the rollers is avoided with certainty.

The acidification may be carried out in various ways. Troughs may be arranged underneath the stretching or guiding rollers intowhich the said'rol'lers dip so that'the hardening liquid attached to them is carried along by adhesion and covers the rollers in the form of a thin layer. By this means the thread is brought into contact with the hardening liquid in the course of its motion over the roller. Further one or both rollers may be sprayed with acid from above or below. and the liquid dropping off the roller may be caught in a collecting trough.

Finally it is possible to carry out a stretch spinning with displaced rollers. The one, driven, roller is arranged directly under the spinning apparatus, whilst another roller is above and displaced with respect to the first. The threads issuing vertically downwards from the spinning apparatus is guided over half the circumference of the roller arranged directly under the orifice of the spinning apparatus, is guided vertically upwards after leaving this roller, is passed over the upper half of the circumference of the roller displaced with respect to the first roller and is led to a centrifuge, to a reel or to a bobbin. In this way, firstly a comparatively low structural height for the machine is obtained and secondly both rollers are uniformly embraced by the thread over half the circumference. The two last named constructional lower end of said vessel,-a tube for-leading 'ments, comprising extruding a cellulosicsolution into a downwardly moving stream of precipitating liquid, diverting precipitating liquid from the filaments by retarding the movement of the precipitating liquid with the filaments'and siphoning ofi precipitating liquid above the point of retardation, the proportion of liquid continuing with the filaments being controlled 'by regulating the quantity of liquid siphoned ofi.

6. In the preparation of cellulosic filaments, the steps comprising extruding a cellulosic solution into a downwardly moving stream of precipitating liquid and diverting the precipitating liquid from the filaments while moving the latter in the same direction into a hardening liquid.

stream of precipitating liquid downwardly through the spinning vessel in contact-with the filaments, and means for diverting the precipitating liquid from the filaments while continuing the movement of the latter in the same direction. V

9. An apparatus of the class described, comprising a spinning nozzle, a downwardly extending tube positioned below said spinning nozzle and adapted to receive the filaments extruded therefrom, means for passing a stream of precipitating liquid through said tube and means for diverting the'precipltating liquid from the filaments while moving in a downwardly direction.

10. An apparatus of the class described,

comprising a spinning vessel, a spinning nozzle, a spinning nozzle arranged at the upper end. of said vessel, an inlet connected with said vessel, an outlet tube arranged at the away used precipitant located above the orifice of said outlet tube and having means associated therewith for regulating the flow of the used precipitant.

11. An apparatus of the class described, comprising a spinning vessel, a spinning nozzle arranged at the upper end of said vessel,

an inlet connected with said vessel, an outlet tube arranged at the'lower end of 'said vessel, a tube for leading, away used precipitant located above the orifice of said outlet tube and means in said tube 'for regulating the! flow of the used precipitant. g

12. In a device of the class described, a

. spinning a spinning vessel, a spinning nozzle arranged at the upper end of said vessel, an inlet for the precipitant, a narrow outlet tube arranged at the lower end of said vessel, and asiphon tube positioned above the orifice of said outlet tube, said siphon tube extending intoa vessel having a liquid level above the outlet of the siphon tube.

13. In a device of the class described having a spinning vessel, a ranged at the upper end ofsaid vessel, means i for supplyingprecipitating liquid to said-vessel, a narrow outlet tube arranged at the bottom of said vessel, :1 siphon tube connected with the lower part of the vessel above the orifice of the outlet tube, said siphon tube extending into a vessel having a liquid level adjustable vertically relative to the outlet of the said outlet tube.

14. In an apparatus of the class described,. a spinning nozzle, a downwardly extending tube adapted to receive filaments extruded from the spinning nozzle, means for supply ing precipitatingliquid to said tube and a piece of material, having a greater adhesion to the precipitating liquid than the filaments, positioned so as to contact'with the precipitating liquid leaving the tube and to divert it fromthe filaments.

15; In an apparatus of the class described, nozzle, a downwardly extending stretch spinning tube positioned to receive filaments extruded from the spinning nozzle, means for supplying precipitating liquid to the upper end of the spinning tube, and a piece of metal, having greater adhesionl or the precipitating liquid than do the filaments, positioned so as to contact with the liquid leaving the spinning tube and bent to divert the stream of liquid from the filaments.

16. A process for producing cellulosic filaments, comprising extruding a cellulosic solution to form filaments, stretching the extruded filaments by the motion of a stream of precipitating liquid, drawing off a portion of the precipitating liquid. while retarding the movement of the liquid with the filaments and diverting the remainder of the precipitating liquid from the filaments after pass ing through the orifice.

17 In a device of the class described, a spinning apparatus having a restricted orifice through which the filaments pass, means for extruding a spinning solution thereinto, means for supplying a'fiow of precipitating liquid to the said spinningapparatus, an outlet for used precipitating liquid above the saidorifice and means for diverting the remainder of the precipitating liquid from the filaments after passing through the orifice and while moving in the said direction.

In testlmony whereof we affix our signatures.

AUGUST HAR'IMANN. WALTER HOFINGHOFF.

spinning nozzle ar- 1 

